1. Field of the Invention
The present invention relates to a ceramic electronic part for high frequency with improved adherence strength between a ceramic material and an electrode, each constituting the ceramic electronic part and to a method for the preparation of the same.
2. Description of the Related Art
As a raw material for a ceramic material of a ceramic electronic part for high frequency, there have been proposed dielectric ceramic compositions containing a composite oxide of barium (Ba), titanium (Ti) and a rare earth elements (Ln) with bismuth (Bi) and/or lead (Pb) as a major component. Ceramic materials consisting of such dielectric ceramic compositions, however, are insufficient in an adherence strength with an electrode so that demands to improve such adherence strength have been made.
In order to improve an adherence strength between a ceramic material and an electrode, attempts have been proposed, for example, to use an electrode paste in which a small amount of a component capable of causing a chemical reaction with the ceramic material is added or to form an anchor point on the surface of a ceramic material by a chemical treatment using hydrofluoric acid or the like.
When the electrode paste containing such a minute amount of the component capable of inducing a chemical reaction is used to improve the adherence strength between the ceramic material and the electrode, however, the electrode paste suffers from the problem that the such minute component added thereto may raise a specific resistance to the electrode leading to a remarkable reduction in high frequency features of ceramic electronic parts resulting therefrom.
On the other hand, when the attempt to improve the adherence strength between the ceramic material and the electrode has been made by forming the anchor point on the surface of the ceramic material by a chemical treatment, the problems may arise that substances resulting from the reaction with a treatment liquid may be left untreated on the surface thereof, thereby failing to achieve a sufficient adherence strength and worsening high frequency characteristics of resulting ceramic electronic parts to a considerable extent. Moreover, this procedure causes the problem that it requires the use of a dangerous chemical substance such as hydrofluoric acid or the like as a treatment liquid and it may give rise to a hazard to working.